AA 7055 aluminium alloy has been widely applied in aviation and aerospace applications, especially after T7751 heat treatment, owing to its excellent properties, such as high strength and good stress corrosion and fatigue resistances. For 7XXX aluminium alloys, aging hardening is the main strengthening mechanism, and the hardening effect is determined by the microstructural features of precipitates including morphology, composition, volume fraction, nucleation density, and size distribution. To further improve the property of alloy and expand the breadth of applications, establishing a precise predictive model regarding strength performance associated with the precipitates is necessary. In this work, based on the quantitative results of the precipitates obtained using small angle X-ray scattering techniques, the strengthening models of AA 7055 Al alloys aged at 120 and 160^oC were investigated. Precipitation kinetics show that at the early stages of aging, the evolution of radius and the half thickness of plate-like precipitates are both linear with t^1/2 (t means the aging time). Conversely, at the later stages of aging, they are linear with t^1/3. The evolution of the volume fraction of the precipitates follows a JMA (Johnson-Mehl-Avrami)-type equation. Strength contributions from both GPI zones and η' precipitates are considered. Moreover, strengthening modeling considered both the modulus and coherency strain strengthening mechanisms of these two kinds of precipitates that had been built for the AA 7055 Al alloy aged at 120 and 160^oC. Therefore, yield strength during aging can be predicted.